Call-bell.



H. G. WEBSTER.

Patented Mar. 17, 1914.

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HARRY G. "WEBS'I'ER, OF CHICAGO, ILLINOIS.

CALL-BELL.

Spfcication of Letters Patent.

Patented Mal'. 17, 1914.

Original application sied March 11, 1912, Serial No. 682,994. Divided and this application filed December To al?? tifmr/ '[1" muy foncer/if ii it known that. l', HARRY G. Nn-155mm, n of the United States of America, .unl i lern ci Chicago, county of Cook, und citate oi lli ois, have invented certain new and fui improvements in Calhells, ot which tho olowing is a specification.

My invention relates to call bells such as :rre used in telephone systems and more pan ticulariy to c: "l'bclls used in soraflled har4 monie selective systems.

The objectoi the invention is to provide novel bell which will insure greater accuracy and eiliciency in operation than is now commonly obtained by bells oi this class.

The present. invention particularly use-- ul in systems of the character described and claimed in my prior application Serial No. 682,224, tiled March 11, 1912, and the present application. is a division ot that ap plication. .is stated in that. application, in be o? the prior nrt, such as illustrated 1n the patents to Denn, No. 779,533, issued Jan. 1t). 1MB, and tn North, No. 1003232, issued Noi'. 1911, '.1 polarized armature, forming t :he reedeieniliei' of each bell, vi

C ilih'il't?. 1:1*

i ized by cach frequency uit that impressed upon n. well known fact that impri ,d upon a polarized "e of this ennrncicr. the armature will be attracted tonzu'il [but pole of Ithe electroy magnet to which it. is nearest. The mechanical Vstrc ses do not correspond in direction to the nnpivessetl current. This appears to be duo to the fact that both polar extremities of the elfi:troinng'nct act directly on the reed armature. The result is in some instances a false response to currents of frequencies other than that for which the device is intended, and in other instances a failure to respond and attain full amplitude of vibration in respense to ihc intended frequency. ln-contrast to this. l so organize the parts of my device flint the magnetism set up by the impressed current impulses produces mechaniwhich correspond in direction and with the impressed currentimindcoendently of the momentary poanions of tue reed-member. In my device ineen the poles of an,

Serial No. 739,330.

there is correspondence between the mechanical stresses and the current impulses. This appears to be due to the fact that but one polar extren'iity of the electromagnet acts directly on the reed-member. This organizat ion of ports, which results in changing the energy of the electric impulses into mechanicnl stresses agreeing with the impulses in direction and frequency, coperates With the tuned reed-member, which has a characteristic rate of vibration, to bring about an improved action in devices of this class.

.ln tho accompanying diagram, I have ill nstrzitod two embodiments of my invention, which obviously may take other forms as well. vFrom these a fuller understanding of the invention will be obtainable, and the scope of the invention will be particularly pointed out in the appended claims.

In said diagram, Figures 1, 2 and 3, illustrate one exni'iodiment, Fig. 1 being a plan f view, Fig. 2, a side view, and Fig. 3, a view of the armature end of the device. Figs. 4 and illustrate thel second embodiment, Fig. 4 boing n partial plan View and Fig. 5 a sectional end view, the section being taken on a plane indicated by the line 5-5 of F ig. 4.

Throughout. these views like characters refer to like paris. y

'Referring now to the mechanical structure of the first form oi' my invention, 25 designates a mounting plate slotted at 26, 26, for the reception of the gong posts 29, 29, and having turned up ears 27, 27, 27, 27, in which turn the adjustment screws 28, 28. These screws are threaded in the posts 29, 29, and serve to hold and move the posts in the slots 26 and thus adjust the gongs 30 with respect to the tapper Weight 41. The curved permanent magnet 31 1s secured to the mounting plate by bolts 44, 44, and has its opposite poles N, S, perforated for the rece tion of, the soft iron bolts 32, 32, Whose hea s 33, 33, constitute adjustable polepieces for the permanent. magnet. The armature consists of the two angular pieces 39,

end of the leaf-spring is securely clamped between the soft iron locks 37, 3T.by means of the non-magnetic angle pieces 35, 35,. and

the bolts, or rivets, 38, 38. The pieces 35 are slotted at 51, 51, to receive the bolts 32, and i when clamped against the ends of magnet 31, serve to rigidly support the armature Btl, 39, at a lixed distance from the magnet ends, The non-magnetic nuts 34, 34, and iron nuts, 36, 36, serve to hold the pieces 35, 35, in place; and also provide means for adjusting the bolt heads 33, 33, with respect to the armature 3), 39, and so varying the air gap for the armature. Air gap spacers of'nonrmagnetic metal may be fixed in the armature or bolts, or these parts may be plated with copper if desired. The electromagnet 45 consists of a single spool having its core secured at one end to the ends of the pieces 3T, 3T, by means of the screws 47 and 46, and at the other end by the screw 48 to the soft iron piece 32 carried on the mounting plate 25. T he electromagnct may be provided with any suitable winding. one such being of approximately 12,060 turns of No. 33!

single silk covered copper wire, having a resistance of approximately 500 ohms.

The structure is one having no break in the magnetic circuit of the permanent magnet or electromagnet,y except at the operating air gap of the armature. W'hen assembled as above, the entire device constitutes a rigid unitary structure in which the armature pieces 39, the leaf-spring 50, the rod 40 and tapperweight 41, constitute a reed-member or reed-striker having a characteristic rate of.vibration. It is adjusted during assembly for currents of predetermined frequency b'Y varying the operating air gap and the ength and stiifness of the leaf spring, and by varying the tapperweight withl respect to its size and to its position on the tapper rod.

In the second forni of my invention, illustrated in Figs. 4 and 5, the mounting plate 61 corresponds to plate 25 of Fig. 1 and is to be understood as adjustably supporting gong-posts and gongs in a similar manner. The permanent magnet 62 is secured to the late 61 by bolts or screws 64', and between its two legs is mounted the electromagnet 63. The electromagnet core is secured at one end to the plate 61 and magnet 62 by means of the screw 65, or in any other suitable manner; and the opposite end is provided with a slot 73, and enlarged portions 64, 64, for supporting the reed-member. This reedmember consists of the two soft iron armature pieces 72, 72, the tapper rod 66, the tapper weight 67, and the leaf-spring 68. One end of the tapper rod, and one end of the leaf-spring are rigidly clamped between the armature pieces 72, by means of rivets, as indicated at 76. The other end of the leaf-spring is rigidly supported in the slot 73, between the core portions 64, by means of rivets or bolts, as indicated at 71 71. Non-magnetic stops may be provided, as indicated at 70, or in any suitable manner. The end portions 69, 69, of magnet 62, constitute opposite poles, and the electroma net may have 8,000, or an other suitab e number of turns in its Win ing. AS so '0rganized, the reed-member has a characteristie rale of vibration, themagnetic circuit is practically unbroken, except at the operating air gap which may be given a permanent adjustment, and the device as a whole is compact, rigid, efficient, and economical to manufacture.

With either embodiment of my invention, when alternating currents are impressed upon the electromagnet winding, the arma.- turealways` receives an active magnetic polarity when current flows in one direction, and an active and opposite magnetic po` larity when current flows intheother direction. Thus, regardless of the position of the. armature, the reed-member always receives an active stress in one direction in resijionse to current impulses of one polarity, and an active stress in the other direct-ion in response to current impulses of the opposite polarity. As thus organized, the present device bas many advantages over prior tuned reed bells, aside from those advantages already pointed out. One characteristic of prior reed bells of the polarized type is found in the more or less well known fact that when impressing relatively strong current impulses of that frequency for which the bell adjusted, if the bell armaturejbe at that instant slightly .ibrating, as from,` a prmious ring, it will frequently fail to respond and ring the bell, and instead will vibrate continuously at small amplitude "asn long as the ringing circuit remains closed.` 'lhis faultjv opcratioIfseems to be dueto the reed motion getting into and remaining in a phase relation with respect to the 1mpressed current. under which it is displaced practically one. hundred and eighty degrees from that phase relation under which its greatest amplitude ofvibration can be secured, Its frequent ocqirrence is just ob jectionable in practice as if the reed-tongue remained motionless.- In the device of ,the present application, the characteristic just described is wholly absent;and instead the reed-member invariably and fquickly as sumes its full amplitude of vibration under all operative condition/s. The device has an etliciency and a positiveness of operation not found in any prior devices of this art, so far as I am aware.

All of the above statements, as to operation, I' have fully verified by actual tests.

I will also be apparent that in practising my invention many alterations and modittcations maybe made in the embodnmnts its bi tion and eopending in direction and frequency to the impressed current impulses will be appiied to said striker independently of its momentary positions.

2. A call bell coniprisin a tuned reedstriker having a characteristic rate of vibration and means where-by sinusoidal currents will, apply to said striker approximately sinusoidal stresses corresponding to said currents in direction and frequency independently of the momentary positions of' said. striker. l 2a 3. A call hbell eomprisinga reed-member A having a characteristic rate of vibration, and inieans, including a. permanent magnet and eneectromagnet of which said reed-member is a polar extension, whereb magnetic stresses corresponding in direction and frequency to the impressed, .current impulses will be applied to said member independ- -ently of its momentary positions.

A call bell compri-sing a reed-member :shaving a characteristic rate of vibration,

"and means, including a permanent magnet and an electromagnet having in their mag netic circuits operating air aps between 'Said member and the poles o said permanent magnet, whereby magnetic stresses corresponding in direction and requency to the impressed current impulses will be applied to saidl member independently of its inomentary positions.

5. Abell bell comprising a permanent magnet, a. reed-nieinber adapted to be tuned to vibra-te at one rate only, said member inelnding an armature mounted interinediate of the poles of said magnet and operatively te to said poles, magnetic circuit e" ,.eetirms rigidly secured to an intermecint of said permanent magnet and ing therefrom to said armature.

call boli. comprising a permanent a reed-member adapted to he tuned ate et one rate only, said member inan armature mounted intermediate atively related to said poles, Vand circuit connections rigidly secured set, an eleetroinaanet rigidi" related to e ncles of said magnet and having itsl said permanent magnet and having its core included in magnetic circuit with portions of said permanent magnet and a reedLmember adapted to be tuned to vibrate at one rate only, said member including an armature operatively related to the poles of said magnets and providing in the magnetic circuits of the device operating air gaps at the poles of said permanent magnet.

8. A call bell comprising a permanent magnet, an electromagnet having its core rigidly related to said permanent magnet and magnetically connectedwith an intermediate point of said permanent magnet,-

and a reed-member adapted to be tuned to vibrate at one rate only, said member including an armature constituting a polar extension ot said electromagnet.

9. A call bell coniprisin a permanent magnet, an clectromagnet aving its core rigidly related to said'permanent magnet and magnetically connected with an intermediate point of said permanent magnet, and a reed-member adapted to be tuned to vibrate at one rate only, said member including an armature constituting a polar extension of one of said magnets and hav! ing its ends operatively related to the poles of the. other of said magnets.

10. A call bell comprising a permanent magnet, an electromagnet having its core rigidly related to said permanent magnet, and a reed-member adapted to be tuned to vibrate at one rate only, said member includin an armature constituting a polar extension of the core of said electromagnet and having its ends operatively related to the poles of said permanent-magnet.

11. A call bell comprising aperrnanent magnet terminating in adjacent poles, an

electromagnet having its core extended to.

an intermediate point of said permanent magnet, and 'terminating in a pole positioned between said permanent magnet poles, and a reed-armature mounted upon said core and extending into operative relation with the poles of said pernianentnagnet.

12. A call bell comprising a permanent magnet terminating in adjacent poles, an clcetromagnet having one end extended to an intermediate portion of said permanent magnet and the other end terminating between said poles, an armature extending bctween and operatively related to said poles, and a supporting reed uniting an intermediate point of said armature to the adja cent end of said electroniagnet.

i3. A call bell comprising gongs, a suitable supporting member for said gongs, a permanent magnet secured at a central point, to said member and havin its ends extending therefrom and terminating in ad jacent poles, ar eleetromagnet having one end secured to said permanent magnet at said central point and the other end terminating between said poles, an armature exl tending between and operatively related to said poles, a 'zapper rod secured to said armature-and extending into operative `rel lation to said gongs, and a supporting reed uniting the adJacent end of said electromag` net to a central portion of said armature.

In witnesA whereof, I hereunto subscribe my name this 28th day of Dec. A. D. 1912. HARRY G: WEBSTER.

'VVtnesseS-z ,'1, H. FERGUSON..

L E. LARSEN. 

